A radargram from the Shallow Subsurface Radar instrument (SHARAD) on NASA's Mars Reconnaissance Orbiter reveals detailed structure in the polar layered deposits of Mars' south pole.

The horizontal scale of the radargram is distance along the orbiter's ground track, about 650 kilometers (400 miles) from about 74 degrees south latitude on the left to about 85 degrees south latitude at right. The vertical scale is time delay of radar signals reflected back to the spacecraft from the surface and subsurface. For reference, the white double-headed arrow indicates a distance of about 800 meters (2,600 feet) between one of the strongest subsurface reflectors and ground level, based on an assumed velocity of the radar waves in the subsurface. This reflector marks the base of the polar layered deposits. The color scale varies from black for weak reflections to white for strong reflections.

The sounding radar collected the data presented here during orbit 1360 of the mission, on Nov. 10, 2006.
The Shallow Subsurface Radar was provided by the Italian Space Agency (ASI). Its operations are led by the University of Rome and its data are analyzed by a joint U.S.-Italian science team. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington.

Image credit: NASA/JPL-Caltech/ASI/University of Rome/Washington Universtiy in St. Louis

A radargram from the Shallow Subsurface Radar instrument (SHARAD) on NASA's Mars Reconnaissance Orbiter is shown in the upper-right panel and reveals detailed structure in the polar layered deposits of the south pole of Mars.

The sounding radar collected the data presented here during orbit 1360 of the mission, on Nov. 10, 2006.

The horizontal scale in the radargram is distance along the ground track. It can be referenced to the ground track map shown in the lower right. The radar traversed from about 74 degrees to 85 degrees south latitude, or about 650 kilometers (400 miles). The ground track map shows elevation measured by the Mars Orbiter Laser Altimeter on NASA's Mars Global Surveyor orbiter. Green indicates low elevation; reddish-white indicates higher elevation. The traverse proceeds up onto a plateau formed by the layers.

The vertical scale on the radargram is time delay of the radar signals reflected back to Mars Reconnaissance Orbiter from the surface and subsurface. For reference, using an assumed velocity of the radar waves in the subsurface, time is converted to depth below the surface at one place: about 800 meters (2,600 feet) to one of the strongest subsurface reflectors. This reflector marks the base of the polar layered deposits. The color scale varies from black for weak reflections to white for strong reflections.

The middle panel shows mapping of the major subsurface reflectors, some of which can be traced for a distance of 100 kilometers (60 miles) or more. The layering manifests the recent climate history of Mars, recorded by the deposition and removal of ice and dust.

The Shallow Subsurface Radar was provided by the Italian Space Agency (ASI). Its operations are led by the University of Rome and its data are analyzed by a joint U.S.-Italian science team. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington.

Image credit: NASA/JPL-Caltech/ASI/University of Rome/Washington University in St. Louis

A radargram from the Shallow Subsurface Radar instrument (SHARAD) on NASA's Mars Reconnaissance Orbiter reveals detailed structure in the polar layered deposits of Mars' north pole. The layering is a manifestation of the recent climate history of Mars as recorded in the deposition and removal of ice and dust.

The horizontal scale of the radargram is distance along the orbiter's ground track, which is about 180 kilometers (110 miles). The vertical scale is time delay of radar signals reflected back to the spacecraft from the surface and subsurface. The color scale varies from black for weak reflections to yellow for strong reflections.

Subsurface layering evident in the radargram is divided into a finely structured upper unit about 600 meters (2,000 feet) thick, and a less well defined set of layers in a lower unit. The base of the entire stack of layers is marked by a very diffuse, bright reflection whose maximum depth is about 2,000 meters (6,600 feet).

The sounding radar collected the data presented here during orbit 1512 of the mission, on Nov. 22, 2006.

The Shallow Subsurface Radar was provided by the Italian Space Agency (ASI). Its operations are led by the University of Rome and its data are analyzed by a joint U.S.-Italian science team. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington.

Image credit: NASA/JPL-Caltech/ASI/University of Rome/Washington University in St. Louis

A radargram from the Shallow Subsurface Radar instrument (SHARAD) on NASA's Mars Reconnaissance Orbiter is shown in the upper-right panel and reveals detailed structure in the polar layered deposits of the north pole of Mars (with blowups shown in the upper-left panels).

The sounding radar collected the data presented here during orbit 1512 of the mission, on Nov. 22, 2006.
The horizontal scale in the radargram is distance along the ground track. It can be referenced to the ground track map shown in the lower right. The radar traversed from about 83.5 degrees to 80.5 degrees north latitude, or about 180 kilometers (110 miles). The ground track map shows elevation measured by the Mars Orbiter Laser Altimeter on NASA's Mars Global Surveyor orbiter. Green indicates low elevation; reddish-white indicates higher elevation. The traverse is from the high elevation of the plateau formed by the layers to the lowlands below.

The vertical scale on the radargram is time delay of the radar signals reflected back to Mars Reconnaissance Orbiter from the surface and subsurface. For reference, using an assumed velocity of the radar waves in the subsurface, time is converted to depth below the surface in two places: about 600 meters (2,000 feet) to the lowest of an upper series of bright reflectors and about 2,000 meters (6,500 feet) to the base of the polar layered deposits. The color scale of the radargram varies from black for weak reflections to bright yellow for strong reflections.

The lower-left panel is a image from the Mars Orbiter Camera on Mars Global Surveyor showing exposed polar layering in the walls of a canyon near the north pole. The layering is divided into a finely structured upper unit (labeled "Upper PLD") and less-well-defined stratigraphy in the lower unit (labeled "Lower PLD"). The radargram clearly reveals the complexity of the layering in the upper unit, additional reflections from the lower unit, and the base of the entire stack of layered deposits. The layering manifests the recent climate history of Mars, recorded by the deposition and removal of ice and dust.

The Shallow Subsurface Radar was provided by the Italian Space Agency (ASI). Its operations are led by the University of Rome and its data are analyzed by a joint U.S.-Italian science team. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington.

Image credit: NASA/JPL-Caltech/ASI/University of Rome/Washington University in St. Louis/MSSS

A radargram from the Shallow Subsurface Radar instrument (SHARAD) on NASA's Mars Reconnaissance Orbiter reveals detailed structure in the polar layered deposits of Mars' south pole.

The horizontal scale of the radargram is distance along the orbiter's ground track, about 590 kilometers (370 miles) from about 75 degrees south latitude on the left to about 85 degrees south latitude at right. The vertical scale is time delay of radar signals reflected back to the spacecraft from the surface and subsurface. For reference, the blue double-headed arrow indicates a distance of about 1,500 meters (5,000 feet) between one of the deeper subsurface reflectors and ground level, based on an assumed velocity of the radar waves in the subsurface. The color scale varies from black for weak reflections to white for strong reflections.

Some of the subsurface reflectors can be traced for a distance of 100 kilometers (60 miles) or more. The layers are not all horizontal and the reflectors are not always parallel to one another. Some of this is due to variations in surface elevation, which produce differing velocity path lengths for different reflector depths. However, some of this behavior is due to spatial variations in the deposition and removal of material in the layered deposits, a result of the recent climate history of Mars.

The sounding radar collected the data presented here during orbit 1334 of the mission, on Nov. 8, 2006.

The Shallow Subsurface Radar was provided by the Italian Space Agency (ASI). Its operations are led by the University of Rome and its data are analyzed by a joint U.S.-Italian science team. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington.

Image credit: NASA/JPL-Caltech/ASI/University of Rome/Washington University in St. Louis

A radargram from the Shallow Subsurface Radar instrument (SHARAD) on NASA's Mars Reconnaissance Orbiter is shown in the upper-right panel and reveals detailed structure in the polar layered deposits of the south pole of Mars.

The sounding radar collected the data presented here during orbit 1334 of the mission, on Nov. 8, 2006.

The horizontal scale in the radargram is distance along the ground track. It can be referenced to the ground track map shown in the lower right. The radar traversed from about 75 to 85 degrees south latitude, or about 590 kilometers (370 miles). The ground track map shows elevation measured by the Mars Orbiter Laser Altimeter on NASA's Mars Global Surveyor orbiter. Green indicates low elevation; reddish-white indicates higher elevation. The traverse proceeds up onto a plateau formed by the layers.

The vertical scale on the radargram is time delay of the radar signals reflected back to Mars Reconnaissance Orbiter from the surface and subsurface. For reference, using an assumed velocity of the radar waves in the subsurface, time is converted to depth below the surface at one place: about 1,500 meters (5,000 feet) to one of the deeper subsurface reflectors. The color scale varies from black for weak reflections to white for strong reflections.

The middle panel shows mapping of the major subsurface reflectors, some of which can be traced for a distance of 100 kilometers (60 miles) or more. The layers are not all horizontal and the reflectors are not always parallel to one another. Some of this is due to variations in surface elevation, which produce differing velocity path lengths for different reflector depths. However, some of this behavior is due to spatial variations in the deposition and removal of material in the layered deposits, a result of the recent climate history of Mars.

The Shallow Subsurface Radar was provided by the Italian Space Agency (ASI). Its operations are led by the University of Rome and its data are analyzed by a joint U.S.-Italian science team. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington.

Image credit: NASA/JPL-Caltech/ASI/University of Rome/Washington University in St. Louis

This image of the Nili Fossae region of Mars was compiled from separate images taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and the High-Resolution Imaging Science Experiment (HiRISE), two instruments on NASA's Mars Reconnaissance Orbiter. The images were taken at 0730 UTC (2:30 a.m. EDT) on Oct. 4, 2006, near 20.4 degrees north latitude, 78.5 degrees east longitude. CRISM's image was taken in 544 colors covering 0.36 to 3.92 micrometers, and shows features as small as 18 meters (60 feet) across. HiRISE's image was taken in three colors, but its much higher resolution shows features as small as 30 centimeters (1 foot) across.

CRISM's sister instrument on the Mars Express spacecraft, OMEGA, discovered that some of the most ancient regions of Mars are rich in clay minerals, formed when water altered the planet's volcanic rocks. From the OMEGA data it was unclear whether the clays formed at the surface during Mars' earliest history of if they formed at depth and were later exposed by impact craters or erosion of the overlying rocks. Clays are an indicator of wet, benign environments possibly suitable for biological processes, making Nili Fossae and comparable regions important targets for both CRISM and HiRISE.

In this visualization of the combined data from the two instruments, the CRISM data were used to calculate the strengths of spectral absorption bands due to minerals present in the scene. The two major minerals detected by the instrument are olivine, a mineral characteristic of primitive igneous rocks, and clay. Areas rich in olivine are shown in red, and minerals rich in clay are shown in green. The derived colors were then overlayed on the HiRISE image.

The area where the CRISM and HiRISE data overlap is shown at the upper left, and is about 5 kilometers (3 miles) across. The three boxes outlined in blue are enlarged to show how the different minerals in the scene match up with different landforms. In the image at the upper right, the small mesa -- a flat-topped hill -- at the center of the image is a remnant of an overlying rock layer that was eroded away. The greenish clay areas at the base of the hill were exposed by erosion of the overlying rock. The images at the upper right and lower left both show that the reddish-toned olivine occurs as sand dunes on top of the greenish clay deposts. The image at the lower right shows details of the clay-rich rock, including that they are extensively fractured into small, polygonal blocks just a few meters in size. Taken together, the CRISM and HiRISE data show that the clay-rich rocks are the oldest at the site, that they are exposed where overlying rock has been eroded away, and that the olivine is not part of the clay-rich rock. Rather it occurs in sand dunes blowing across the clay.

Many more images of Nili Fossae and other clay-rich areas will be taken over the next two years. They will be used to try to understand the earliest climate of Mars that is recorded in the planet's rocks.

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is one of six science instruments on NASAís Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad.

CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and map the geology, composition and stratigraphy of surface features. The instrument will also watch the seasonal variations in Martian dust and ice aerosols, and water content in surface materials -- leading to new understanding of the climate.

NASA's Jet Propulsion Laboratory, a division of the Califonia Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor and built the spacecraft.

This Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) ìtargeted image" shows a region of sand dunes surrounding the Martian north polar cap. CRISM, an instrument on NASA's Mars Reconnaissance Orbiter, acquired the image at 1811 UTC (2:11 p.m. EDT) on Oct. 1, 2006. The imaged site is near 80.0 degrees north latitude, 240.7 degrees east longitude. It covers an area about 12 kilometers (7.5 miles) square. At the center of the image, the spatial resolution is as good as 20 meters (65 feet) per pixel. The image was taken in 544 colors covering 0.36 to 3.92 micrometers.

CRISM's sister instrument on the Mars Express spacecraft, OMEGA, has spectrally mapped Mars at lower spatial resolution and discovered that several regions of the planet are rich in sulfate minerals formed by liquid water. Surprisingly, one of the sulfate-rich deposits is a part of the giant field of sand dunes surrounding the north polar cap. CRISM is remapping the dune field at about five times higher resolution than OMEGA, and imaging selected regions at 50 times higher resolution. This image is the first of the high-resolution images of the dune field.

This visualization includes two renderings of the data, both map-projected. The left images are false-color representations showing brightness of the surface at selected infrared wavelengths. The right images show strength of an absorption band at 1900 nanometers wavelength, which indicates the relative abundance of the sulfate mineral gypsum. Brighter areas have more gypsum, and darker areas have less gypsum. The bottom views are enlargements of the central part of the two versions of the image shown at top.

Gypsum is a light-colored, whitish mineral, so it was anticipated that gypsum-rich parts of the sand dunes would be light in color. In fact, there are light-colored areas in the left images, but the images of the gypsum absorption at right show that the light areas have only low gypsum abundance. The dark sand dunes contain most of the gypsum, which is particularly concentrated at the dune crests. CRISM's scientists are taking more high-resolution images of the dune fields to see if this pattern is prevalent, and to attempt to track down the source of the gypsum that makes an arid dune field so rich in minerals formed long ago in liquid water.

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is one of six science instruments on NASAís Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad.

CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and map the geology, composition and stratigraphy of surface features. The instrument will also watch the seasonal variations in Martian dust and ice aerosols, and water content in surface materials -- leading to new understanding of the climate.

NASA's Jet Propulsion Laboratory, a division of the Califonia Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor and built the spacecraft.

This false-color subframe of an image from the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter shows the north polar layered deposits at top and darker materials at bottom, exposed in a scarp at the head of Chasma Boreale, a large canyon eroded into the layered deposits.

The polar layered deposits appear red because of dust mixed within them, but are ice-rich as indicated by previous observations. Water ice in the layered deposits is probably responsible for the pattern of fractures seen near the top of the scarp. The darker material below the layered deposits may have been deposited as sand dunes, as indicated by the crossbedding (truncation of curved lines) seen near the middle of the scarp. It appears that brighter, ice-rich layers were deposited between the dark dunes in places. Exposures such as these are useful in understanding recent climate variations that are likely recorded in the polar layered deposits.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

This full-frame image from the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter shows faults and pits in Mars' north polar residual cap that have not been previously recognized.

The faults and depressions between them are similar to features seen on Earth where the crust is being pulled apart. Such tectonic extension must have occurred very recently because the north polar residual cap is very young, as indicated by the paucity of impact craters on its surface. Alternatively, the faults and pits may be caused by collapse due to removal of material beneath the surface. The pits are aligned along the faults, either because material has drained into the subsurface along the faults or because gas has escaped from the subsurface through them.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

This frame from the microscopic imager on NASA's Mars Exploration Rover Opportunity shows spherules up to about 5 millimeters (one-fifth of an inch) in diameter. The camera took this image during the 924th Martian day, or sol, of Opportunity's Mars-surface mission (Aug. 30, 2006), when the rover was about 200 meters (650 feet) north of 'Victoria Crater.'

Opportunity discovered spherules like these, nicknamed "blueberries," at its landing site in "Eagle Crater," and investigations determined them to be iron-rich concretions that formed inside deposits soaked with groundwater. However, such concretions were much smaller or absent at the ground surface along much of the rover's trek of more than 5 kilometers (3 miles) southward to Victoria. The big ones showed up again when Opportunity got to the ring, or annulus, of material excavated and thrown outward by the impact that created Victoria Crater. Researchers hypothesize that some layer beneath the surface in Victoria's vicinity was once soaked with water long enough to form the concretions, that the crater-forming impact dispersed some material from that layer, and that Opportunity might encounter that layer in place if the rover drives down into the crater.

As part of its investigation of "Victoria Crater," NASA's Mars Exploration Rover Opportunity examined a promontory called "Cape Verde" from the vantage point of "Cape St. Mary," the next promontory clockwise around the crater's deeply scalloped rim. This view of Cape Verde combines several exposures taken by the rover's panoramic camera into an approximately true-color mosaic. The exposures were taken during mid-afternoon lighting conditions.

The upper portion of the crater wall contains a jumble of material tossed outward by the impact that excavated the crater. This vertical cross-section through the blanket of ejected material surrounding the crater was exposed by erosion that expanded the crater outward from its original diameter, according to scientists' interpretation of the observations. Below the jumbled material in the upper part of the wall are layers that survive relatively intact from before the crater-causing impact.

The images combined into this mosaic were taken during the 1,006th Martian day, or sol, of Opportunity's Mars-surface mission (Nov. 22, 2006). The panoramic camera took them through the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

View of 'Cape Verde' from 'Cape St. Mary' in Mid-Afternoon (False Color)

As part of its investigation of "Victoria Crater," NASA's Mars Exploration Rover Opportunity examined a promontory called "Cape Verde" from the vantage point of "Cape St. Mary," the next promontory clockwise around the crater's deeply scalloped rim. This view of Cape Verde combines several exposures taken by the rover's panoramic camera into a false-color mosaic. The exposures were taken during mid-afternoon lighting conditions.

The upper portion of the crater wall contains a jumble of material tossed outward by the impact that excavated the crater. This vertical cross-section through the blanket of ejected material surrounding the crater was exposed by erosion that expanded the crater outward from its original diameter, according to scientists' interpretation of the observations. Below the jumbled material in the upper part of the wall are layers that survive relatively intact from before the crater-causing impact.

The images combined into this mosaic were taken during the 1,006th Martian day, or sol, of Opportunity's Mars-surface mission (Nov. 22, 2006). The panoramic camera took them through the camera's 750-nanometer, 530-nanometer and 430-nanometer filters. The false color enhances subtle color differences among materials in the rocks and soils of the scene.

As part of its investigation of "Victoria Crater," NASA's Mars Exploration Rover Opportunity examined a promontory called "Cape Verde" from the vantage point of "Cape St. Mary," the next promontory clockwise around the crater's deeply scalloped rim. This view of Cape Verde combines several exposures taken by the rover's panoramic camera into an approximately true-color mosaic. The exposures were taken during late-morning lighting conditions.

The upper portion of the crater wall contains a jumble of material tossed outward by the impact that excavated the crater. This vertical cross-section through the blanket of ejected material surrounding the crater was exposed by erosion that expanded the crater outward from its original diameter, according to scientists' interpretation of the observations. Below the jumbled material in the upper part of the wall are layers that survive relatively intact from before the crater-causing impact.

The images combined into this mosaic were taken during the 1,006th Martian day, or sol, of Opportunity's Mars-surface mission (Nov. 22, 2006). The panoramic camera took them through the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

View of 'Cape Verde' from 'Cape St. Mary' in Late Morning (False Color)

As part of its investigation of "Victoria Crater," NASA's Mars Exploration Rover Opportunity examined a promontory called "Cape Verde" from the vantage point of "Cape St. Mary," the next promontory clockwise around the crater's deeply scalloped rim. This view of Cape Verde combines several exposures taken by the rover's panoramic camera into a false-color mosaic. The exposures were taken during late-morning lighting conditions.

The upper portion of the crater wall contains a jumble of material tossed outward by the impact that excavated the crater. This vertical cross-section through the blanket of ejected material surrounding the crater was exposed by erosion that expanded the crater outward from its original diameter, according to scientists' interpretation of the observations. Below the jumbled material in the upper part of the wall are layers that survive relatively intact from before the crater-causing impact.

The images combined into this mosaic were taken during the 1,006th Martian day, or sol, of Opportunity's Mars-surface mission (Nov. 22, 2006). The panoramic camera took them through the camera's 750-nanometer, 530-nanometer and 430-nanometer filters. The false color enhances subtle color differences among materials in the rocks and soils of the scene.

As part of its investigation of "Victoria Crater," NASA's Mars Exploration Rover Opportunity examined a section of the scalloped rim called "Bottomless Bay" (or "Bahia sin Fondo"). This view shows the northeastern side of Bottomless Bay as seen from the southwest. The exposures combined into this mosaic were taken by the rover's panoramic camera through a 750-nanometer filter during the 1,019th Martian day, or sol, of Opportunity's Mars-surface mission (Dec. 5, 2006).

As part of its investigation of "Victoria Crater," NASA's Mars Exploration Rover Opportunity examined a section of the scalloped rim called "Bottomless Bay" (or "Bahia sin Fondo"). This view shows the northeastern side of Bottomless Bay as seen from the southwest. The exposures combined into this mosaic were taken by the rover's panoramic camera through a 750-nanometer filter during the 1,019th Martian day, or sol, of Opportunity's Mars-surface mission (Dec. 5, 2006). Contrast has been altered to improve the visibility of details in shadowed areas.

As part of its investigation of "Victoria Crater," NASA's Mars Exploration Rover Opportunity examined a promontory called "Cape St. Mary" from the from the vantage point of "Cape Verde," the next promontory counterclockwise around the crater's deeply scalloped rim. This view of Cape St. Mary combines several exposures taken by the rover's panoramic camera into an approximately true-color mosaic.

The upper portion of the crater wall contains a jumble of material tossed outward by the impact that excavated the crater. This vertical cross-section through the blanket of ejected material surrounding the crater was exposed by erosion that expanded the crater outward from its original diameter, according to scientists' interpretation of the observations. Below the jumbled material in the upper part of the wall are layers that survive relatively intact from before the crater-causing impact. Near the base of the Cape St. Mary cliff are layers with a pattern called "crossbedding," intersecting with each other at angles, rather than parallel to each other. Large-scale crossbedding can result from material being deposited as wind-blown dunes.

The images combined into this mosaic were taken during the 970th Martian day, or sol, of Opportunity's Mars-surface mission (Oct. 16, 2006). The panoramic camera took them through the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

As part of its investigation of "Victoria Crater," NASA's Mars Exploration Rover Opportunity examined a promontory called "Cape St. Mary" from the from the vantage point of "Cape Verde," the next promontory counterclockwise around the crater's deeply scalloped rim. This view of Cape St. Mary combines several exposures taken by the rover's panoramic camera into an approximately true-color mosaic with contrast adjusted to improve the visibility of details in shaded areas.

The upper portion of the crater wall contains a jumble of material tossed outward by the impact that excavated the crater. This vertical cross-section through the blanket of ejected material surrounding the crater was exposed by erosion that expanded the crater outward from its original diameter, according to scientists' interpretation of the observations. Below the jumbled material in the upper part of the wall are layers that survive relatively intact from before the crater-causing impact. Near the base of the Cape St. Mary cliff are layers with a pattern called "crossbedding," intersecting with each other at angles, rather than parallel to each other. Large-scale crossbedding can result from material being deposited as wind-blown dunes.

The images combined into this mosaic were taken during the 970th Martian day, or sol, of Opportunity's Mars-surface mission (Oct. 16, 2006). The panoramic camera took them through the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

As part of its investigation of "Victoria Crater," NASA's Mars Exploration Rover Opportunity examined a promontory called "Cape St. Mary" from the from the vantage point of "Cape Verde," the next promontory counterclockwise around the crater's deeply scalloped rim. This view of Cape St. Mary combines several exposures taken by the rover's panoramic camera into a false-color mosaic. Contrast has been adjusted to improve the visibility of details in shaded areas.

The upper portion of the crater wall contains a jumble of material tossed outward by the impact that excavated the crater. This vertical cross-section through the blanket of ejected material surrounding the crater was exposed by erosion that expanded the crater outward from its original diameter, according to scientists' interpretation of the observations. Below the jumbled material in the upper part of the wall are layers that survive relatively intact from before the crater-causing impact. Near the base of the Cape St. Mary cliff are layers with a pattern called "crossbedding," intersecting with each other at angles, rather than parallel to each other. Large-scale crossbedding can result from material being deposited as wind-blown dunes.

The images combined into this mosaic were taken during the 970th Martian day, or sol, of Opportunity's Mars-surface mission (Oct. 16, 2006). The panoramic camera took them through the camera's 750-nanometer, 530-nanometer and 430-nanometer filters. The false color enhances subtle color differences among materials in the rocks and soils of the scene.

This perspective view looking toward the northeast shows part of the Columbia Hills range inside Gusev Crater. At the center is the winter campaign site of NASA's Mars Exploration Rover Spirit.

On its 805th Martian day, or sol, (April 8, 2006), Spirit was parked on a slope tilting 11 degrees to the north to maximize sunlight on the solar panels during the southern winter season. Science observations were formulated to take advantage of the long time during which the rover was parked. The plan focused on two tasks: tracking atmospheric and surface dynamics by periodically surveying the surface and atmosphere; and extensively examining surrounding terrains, rocks and soils using the panoramic camera and the miniature thermal emission spectrometer, coupled with long duration measurements using the alpha particle X-ray and Mössbauer spectrometers of rock and soil targets. For reference, the feature known as "Home Plate" is approximately 90 meters (295 feet) wide.

An image from Mars Global Surveyor's Mars Orbital Camera, catalogued as E03_00012 and courtesy Malin Space Science Systems, was used as the base image for this figure. The perspective was generated using elevation data generated from analyses of the camera's stereo images by the U.S. Geological Survey, Flagstaff, Ariz.

This portion of an image acquired by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment camera shows the Spirit rover's winter campaign site. Spirit was parked on a slope tilted 11 degrees to the north to maximize sunlight during the southern winter season. "Tyrone" is an area where the rover's wheels disturbed light-toned soils. Remote sensing and in-situ analyses found the light-toned soil at Tyrone to be sulfate rich and hydrated. The original picture is catalogued as PSP_001513_1655_red and was taken on Sept. 29, 2006.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

This portion of an image acquired by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment camera shows the Spirit rover's winter campaign site. The rover is visible. So is the "Low Ridge" feature where Spirit was parked with an 11-degree northerly tilt to maximize sunlight on the solar panels during the southern winter season. Tracks made by Spirit on the way to "Home Plate" and to and from "Tyrone," an area of light-toned soils exposed by rover wheel motions, are also evident. The original image is catalogued as PSP_001513_1655_red and was taken Sept. 29, 2006.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

This is a portion of an image called the "McMurdo Panorama," taken by the panoramic camera on NASA's Spirit rover during its winter campaign of 2006. The view is looking toward the north at "Husband Hill," the dark-toned "El Dorado" dune field and the light-toned "Home Plate" feature. Husband Hill is approximately 850 meters (2,800 feet) from the rover's winter campaign site. Wind-blown ripples are evident in the field in the foreground, along with vesicular basalt rock. Tracks made by Spirit as it left Home Plate are also visible.
The McMurdo Panorama was acquired over several months while Spirit was on "Low Ridge." It required all of the camera's geology filters and covered 360 degrees in azimuth. This view is in false color, with blue, green and red representing data collected through 430-nanometer, 530-nanometer and 750-nanometer filters, respectively.

This is a portion of an image, called the "McMurdo Panorama," taken by the panoramic camera on the Spirit rover during its winter campaign. The view is looking toward the east, at "Tyrone," the light-toned soils exposed by the rover's wheels. The Tyrone area proved difficult for Spirit to get through, so the rover was commanded to traverse to "Low Ridge," the site of the winter campaign. Note the light-toned material in the wheel tracks generated as the rover drove to the site. Several rock and soil targets are shown that were investigated with instruments on the rover's robotic arm.

The McMurdo Panorama was acquired over several months while Spirit was on "Low Ridge." It required all of the camera's geology filters and covered 360 degrees in azimuth. This view is in false color, with blue, green and red representing data collected through 430-nanometer, 530-nanometer and 750-nanometer filters, respectively.

This mosaic was made from frames acquired by the microscopic imager on NASA's Mars Exploration Rover Spirit during Spirit's 1,031 Martian day, or sol, on the red planet (Nov. 27, 2006). It shows a rock target called "King George Island" after the target was brushed by the rover's rock abrasion tool. The mosaic covers approximately 6 centimeters (2.4 inches) across and shows the granular nature of the rock exposure. The grains are typically about 1 millimeter (.04 inches) wide. Data from the rover's Mössbauer spectrometer provides evidence that they have an enhanced amount of the mineral hematite relative to surrounding soils.